Portable jointer knife grinder



Dec. 9, 1952 E. A. DVORAK 7 2,520,606

PORTABLE JOINTER KNIFE GRINDER Filed Jan. 11, 1951 2 SIiEETS-SHEET 1 .ZCJZlhmrdE INVENTOR,

ATTORNEYS Dec. 9, 1952 E A. DVORAK PORTABLE JOINTER KNIFE GRINDER 2 SI-lEETS-Sl-EET 2 Filed Jan. 11, 1951 $.12 Boar @723 INVENTOR ATTORNEYS- Patented D 9 UNITED; STATES PATENT OFFICE j fj2,e2o,eoe V Y PORTABLE JOINTER KNIFE GRINDER Q was A. Dvorak, Edgerton, Wis.

Application January 11, 1951, Serial No. 205,571

1 Claim.

I removing the'knives from the machine to grind or sharpen the knives.

An important object of the invention is to provide a portable jointer knife grinder which may be clamped in position against the knives, the sharpener being movable longitudinally of the blades for sharpening the blades throughout their entire lengths. H j

Another object of the invention is to provide means whereby thegrinding wheel may be adjusted with respect to the bladesbeing ground, to insure the true grinding of the blades.".'

With the foregoing and other objects in view which will appear as the description proceeds, the invention consists of certain novel details of construction and combinations of parts hereinafter more fully described and pointed out in the claim, it being understood that changes may be made in the construction and arrangement of parts without departing from the spirit of the invention as claimed.

Referring to the drawings,

Figure 1 is a side elevational view, illustrating a portable grinding device constructed in accordance with the invention, as mounted on the table of the jointer or planing machine.

Fig. 2 is a front elevational view thereof.

Fig. 3 is a plan View illustrating the grinder attachment as mounted on the jointer.

Fig. 4 is a fragmental perspective View illustrating the grinding device as mounted for grinding a blade of the jointer.

Fig. 5 is a sectional view taken substantially on line 55 of Fig. 2.

Referring to the drawings in detail, the reference character 5 indicates the jointer table which is provided with an opening through which the blades 6 of the rotary cutter I, extend for planing lengths of wood moved over the table.

The rotary cutter is mounted on the shaft 8 and is operated in the usual and well known manner.

The device forming the subject matter of the present invention, embodies a supporting rod 9 which has its ends mounted in the brackets Ill that extend forwardly from the bar II. Secured to the bar II and depending therefrom, is the stop 52 which is adapted to be positioned against one side of the jointer table, the stop 52 cooperating with the head I3 mounted on the inner end of the threaded shank It that moves through the threaded bore formed inthe lug I5. The handle I6 afiords means whereby the threaded shank may be rotated to move the head I3 into clamping relation with the side of the jointer table, as clearly shown by Fig. 2 of the drawings.

The reference character I! indicates the supporting plate of the portable grinding-device, to which the plate I8 is secured as by welding, the plate I8 being disposed at an oblique angle with respect to the supporting plate I has shown by Fig. 5 of the drawings. This plate It is provided with an elongated opening I9 through which the lug 20 extends, the elongated opening providing a guide for the lug,'to insure. true movement of the adjustable support 2i that is provided with a bearing opening in which the shaft 22 operates, the shaft 22 providing a support for the grinding stone 23, the shaft 22 being rotated by a suitable power means indicated by the character A which may be a suitable power tool. As shown by Fig. 5 of the drawings, one end of the plate I8 extends at right angles as at 24, the right angled end of the plate I8 being formed with an opening, through which the shaft 25 extends, the shaft 25 being provided with the collar 26 for restricting movement of the shaft 25 through the opening.

The knob 21 is secured to the shaft 25 and contacts the outer surface of the right angled end 24 of the plate I8, so that the right angled end is clamped between the collar 26 and knob 21. The threaded portion of the shaft 25 extend into the threaded bore 28 of the adjustable support 2|, and by rotating the shaft 25, the threaded portion of the shaft will operate to move the adjustable support 2| longitudinally of the plate I8. A set screw 29 extends through a threaded bore in the lug 20, and contacts with the plate I8, adjacent to the elongated opening I9, securing the adjustable support 2 I, in various positions of adjustment along the plate I8.

As shown, the adjustable support 2| may be moved to extend the grinding stone 23 to the desired position for grinding the knives of the jointer.

The plate I8 is provided with a cut out portion 39 in which the grinding stone 23 operates, the plate I8 being of a length to engage against one side of the blade being sharpened to hold the grinding stone in its proper position.

Mounted on the supporting plate I1, is the handle 3I by means of which the supporting plate I! may be moved longitudinally of the supporting rod 9, thereby moving the grinding stone into engagement with the knife or cutting blade 3 being sharpened, throughout the entire length of the knife or cutting blade.

In order that the rotary cutter i will be held against rotation during the sharpening of the knives or blades carried thereby, the rod 32 is provided, which rod is provided with a hook 33 at its free end, the hook being designed to hook behind a blade 5 of the rotary cutter being sharp ened, the opposite end of the rod 32 passing through an opening in the flange 3-; of the bar 8 i, where it is connected with the coiled spring 35 which spring is anchored to the bar H, at 30. Thus it will be seen that due to this construction, as the grinding stone is being rotated to grind or sharpen a knife or blade of the rotary cutter, the rotary cutter will be held stationary against the rotary action of the grinding stone. While the rod 32 provides means for securing the rotary cutter against rotation while being sharpened, it will be readily seen that the rod may be readily and easily positioned for holding the rotary cutter, or the rod may be removedto release the cutter blades and allow the jointer to operate in the usual manner.

Having thus described the invention what is claimed is:

A portable grinding device for grinding the blades of a jointer having a table, comprising a supporting bar, clamping means for clamping the supporting bar to the table, brackets extending forwardly from said supporting bar, a supporting rod mounted in the brackets and disposed transversely of said table, a supporting plate slidably mounted on said rod at one end of the supporting plate, a plate secured to the forward end of the supporting plate inclined with respect to the supporting plate, the latter plate having a cut-out portion extending inwardly from the forward edge thereof, the forward edge of said latter plate being engageable with the side edge of the jointer blade being sharpened to hold the latter plate against movement in one direction, a grinding stone adjustably mounted on said latter plate and operating through said cut-out portion to grind the jointer blade disposed thereunder, handle rising from said supporting plate effecting movement of said supporting plate and grinding stone transversely of the table and jointer blade being sharpened, and a rod secured at one of its ends to said supporting bar, said rod having a hook at one end thereof adapted to hook over the blade being sharpened to hold the blade in engagement with said latter plate.

EDWIN A. DVORAK.

REFERENCES CITED following references are of record in the idle of this patent:

UNITED STATES PATENTS Number Name Date 279,785 Millar June 19, 1883 831,541 Davis Sept. 25, 1906 900,284 Kahle et al Oct. 6, 1908 990,373 Mitchell Apr. 25, 1911 1,071,580 Ring Aug. 26, 1913 1,187,807 Boling June 20, 1916 1,193,295 Perkins Aug. 1, 1916 1,213,703 Speegle Jan. 23, 1917 1,769,870 Traud July 1, 1930 2,417,373 Morrison Mar. 11, 1947 

